Locking blade for centrifugal blasting wheel



May 26, 1970 J. E. DE GROOT ETAL 3,513,597

LOCKING BLADE FOR CENTRIFUGAL BLASTING WHEEL Original Filed Feb: 1, 1965 2 Sheets-Sheet l w O I m: s Mr a; mm m \NN. W 3 mm A x w INVENTORS. JOHN E DE 6/?007' BERNARD FUERST WUyuya, 7M4 M L Q.

May 26, 1970 J. E. DE GROOT ET 3,

LOCKING BLADE FOR CENTRIFUGAL BLASTING WHEEL Original Filed Feb. 1, 1965- 2 Sheets-Sheet 2 INVENTORS JOHN E 015' 6/?007' BERNARD FUERST United States Patent 3,513,597 LOCKING BLADE FOR CENTRIFUGAL BLASTING WHEEL John E. De Groot and Bernard Fuerst, Grand Rapids, Mich., assignors to The Wheelabrator Corporation, Mishawaka, Ind., a corporation of Delaware Original application Feb. 1, 1965, Ser. No. 429,281, now Patent No. 3,352,064, dated Nov. 14, 1967. Divided and this application July 10, 1967, Ser. No. 652,137 Int. Cl. B24c 3/00 U.S. Cl. 51-9 1 Claim ABSTRACT OF THE DISCLOSURE The invention is addressed to a blade for a centrifugal blasting wheel formed of a pair of axially spaced Wheel members joined one to another with radial grooves extending in parallel relationship along the inner face's of the wheel members for receipt of radially extending blade members over which particulate material is displaced during rapid rotational movement of the wheel. The improvement resides in a means for releasably securing the blades in position of use in the wheel comprising radially spaced abutments the outermost of which is at a higher level than the innermost with a member mounted for rotational movement between the wheels having a central eccentric or cutoff portion adapted to enable the innermost abutment to pass thereunder when in unlocking position and to block the innermost abutment from passage thereunder when in locking position to provide means for releasably securing the blade in position of use with the outermost abutment dimensioned to engage said locking device independent of its position to establish the inserted position for the blade. A further important feature resides in a radially extending arm integral with the locking member centrifngally to urge the locking member in locking position responsive to rotational movement of the wheel thereby to prevent inadvertent release of the blade during operation of the wheel.

This is a division of our co-pending application Ser. No. 429,281 filed Feb. 1, 1965 and entitled Lock System For Blasting-Machine Blades, now Pat. No. 3,352,064, dated Nov. 14, 1967. r

This invention relates to the construction of blasting machines, in which a rotating wheel is used to accelerate abrasive particles to produce a high-velocity stream directable along a selected path. These machines are commonly used in foundries to clean scale from castings, and in many other industrial processes. The usual construction of a rotor includes a pair of disc-shaped side plates separated by spacers, and this assembly is usually fastened to a hub structure mounted on a driven shaft. At least one of the plates is open in the central area, and abrasive par ticles are supplied via this opening to the space between the side plates. Blades supported by the plates engage these particles and accelerate them as the wheel rotates. The result is a tangential stream of high velocity abrasive particles, and erosion of the blades resulting from this action necessitates frequent blade replacement. r-

T he blades are commonly received along their edges in opposite grooves in the rotor side plates. These grooves are normally radial, and means must be providedfor holding the blades against the effects of centrifugal force. In prior machines, this locking action has been provided by set screws in the side plates, or by a locking clip, of the type shown in U.S. Pat. No. 2,819,562. These prior locking arrangements have shown several undesirable characteristics, and the present invention has been developed to provide a blade lock that requires no tools, is not Patented May 26, 1970 "Ice subject to variations in spring strength and dimensions, and is of such sturdy construction as to minimize the danger that stray particles of abrasive will wear enough of the locking device away to endanger the security of the locking action. These blades commonly weigh several pounds, and attain velocities of two hundred feet per second or more. It is obviously vital that the blades be prevented from escaping from the rotor.

The several features of the invention will be analyzed in detail through a discussion of the particular embodiment illustrated in the accompanying drawings. In the drawings:

FIG. 1 is an axial section through a rotor equipped with the present invention for locking the blades in position. The rotor is of otherwise conventional construction.

FIG. 2 is a fragmentary section on the plane 2-2 of FIG. 1.

FIG. 3 is a section on the plane 3-3 of FIG. 1, on an enlarged scale.

FIG. 4 is a section on the plane 44 of FIG. 1, on a scale corresponding to that of FIG. 3.

FIG. 5 illustrates the release position of the locking device.

FIG. 6 is a perspective exploded view showing the relationship of the side plate grooves, and the locking device.

FIG. 7 is a perspective view of the front, or abrasivereceiving, side of the blade.

The rotor generally indicated at 10 includes the axiallyspaced side plates 11 and 12 maintained in parallel spaced relationship by the spacer posts 13-15 shown in FIG. 2. These are uniformly disposed around the rotor. This side plate assembly is secured to the hub structure 16 mounted on the driven shaft 17 in a suitable machine frame (not shown). The side plate 12 has a central opening substantially occupied by the cage assembly indicated generally at 18. The chute 19 delivers a continuous supply of abrasive particles during the operation of the machine, and the functioning of the cage structure is to admit these particles at a selected sector so that the emerging tangential stream of high-velocity particles will be located as desired to follow a predetermined path. It should be noted that the cage structure 18 is fixed in position, and the distributing member 20 is secured to the rotor. The delivery of the particles through the chute 19 to the interior of the distributing member 20 will cause the particles to move around with the rotor until they emerge from the opening 21 in the cage 18 which is appropriately located to produce the desired tangential path of the abrasive particles emerging from the machine. When the particles move radially outward through the opening 21, they begin to encounter the blades shown at 22-25, these blades (together with others) being uniformly spaced about the rotor, and arranged in radial planes containing the axis of rotation of the rotor. The structure thus far described is conventional.

The erosive effect of the stream of high velocity abrasive particles requires frequent replacement of the blades, and somewhat less frequent replacement of the side assembly. The securing of the side plate assembly to the hub structure 16 by the bolts shown at 26 and 27 in FIG. 1 makes the replacement of the side-plate assembly a fairly simple matter. The replacement of the blades necessitates disengagement of a locking system which must be incorporated to prevent centrifugal force from moving the blades outwardly in the retaining slots commonly provided on the inner surfaces of side plates 11 and 12. Referring particularly to FIG. 3, the edges 28 and 29 of the blades are received in opposite grooves as shown at 30 and 31 in the adjacent surfaces of the side plates 11 and 12. The front face of the blade is indicated at 32, which is the face primarily receiving the stream of abrasive particles.

This face corresponds to the advance surface of the blade with respect to the direction of rotation.

Referring particularly to FIG. 6, the back surface of the blade indicated at 33 is provided with axially-spaced pairs of abutments 34-35 and 36-37. The abutments constituting the pairs are radially spaced sufiiciently to admit between them the central portion 38 of the locking member 39. The ends 40 and 41 of the locking member 39 are engageable with opposite recesses as shown at 42 in FIG. 6, and these recesses intersect the retaining grooves receiving the edges of the blades. The central portion 38 is eccentric with respect to the ends 40 and 41, with the result that the locking member 39 is rotatable between a locking position shown in FIG. 4 and a release position shown in FIG. 5. In FIG. 4, the presence of the central portion 38 between the abutments prevents either outward or inward movement of the blades, while the release position of FIG. will permit the blade to be withdrawn to the left so that the abutments 35 and 37 can move underneath the central portion 38 of the locking member. In the release position, it is very convenient to have the abutments 34 and 36 sufficiently high so that they will function as a stop limiting the inward movement of the blades on insertion from the outer periphery of the rotor.

It is significant that the arm 43 is secured to the locking member 39 in a position such that the effect of centrifugal force will normally maintain the locking member in the FIG. 4 position. To release the blade, the arm 43 is swung from the radially outward position of FIG. 4 to the inward position of FIG. 5. The arm 43 is returned to the FIG. 4 position after the new blade has been inserted.

To avoid the possibility that certain of the locking members might assume a position when the rotor is stopped in which the effect. of gravity on the arms 43 might cause an unlocking of the blades, the compression springs 44 are installed in the axial holes 45 in the ends of one side of the locking members. The strength of these springs is selected to produce a frictional effect which will exceed the tendency of gravity to rotate the locking member at any position around its rotary path of movement.

The radially outer abutments 34 and 36 are not necessary to the functioning of the invention, as other structure may be relied upon to establish the stop to the inward movement of the blades on insertion. For example, the radially inner abutments might be disposed to contact the spacers 13-15, or some auxiliary stop structure can be incorporated. It is also clear that it is not vital that a pair of inner abutments as shown at 35-37 be used. As far as the function is concerned, one of these would be adequate. It is preferable, however, that forces be balanced by the structure as shown. It is also preferable that the locking member be provided with cylindrical or camshaped bearing portions as shown at 46 and 47 which bear on the blade to control the degree of looseness of the blades in the grooves.

The conformation of the locking member is determined so that it may be inserted and removed (in the absence of the blade associated with it) without dis-assembly of the side plate structure of the machine. The extent of the recesses 42 to the side of the grooves 31 is related to the length of the locking member between its opposite ends such that placement of the locking member in a diagonal position (inclined with respect to a perpendicular to the side plates) will permit the withdrawal of the locking member, with the assistance of the clearance provided by the slots 31. It will normally be necessary to shove the locking member 39 so as to compress the spring 44 in order to accomplish this insertion or removal, but this presents no problem. The replacement of the locking members is a very infrequent operation, and the compression of the spring 44 can be accomplished through the insertion of a screw driver under the opposite end of the locking member, normally applied through the space provided by the adjacent blade groove.

The particular embodiments of the present invention which have been illustrated and discussed herein are for illustrative purposes only and are not to be considered as a limitation upon the scope of the appended claim. In this claim, it is our intent to claim the entire invention disclosed herein, except as we are limited by the prior art.

We claim:

1. A blade for use with a rotor having spaced parallel side plates perpendicular to the axis of the rotor with radial grooves in adjacent surfaces of said side plates for receipt of the lateral edges of said blade, and a rotatable locking member with an eccentric portion between the plates whereby a greater spaced relationship exists between said eccentric portion and the back side of the blade when in unlocking position than when in locking position: said blade having radially spaced inner and outer pairs of abutments on the back side thereof; the outer pair of abutments dimensioned to extend beyond the level of the inner pair of abutments; and wherein the abutments of each pair are spaced from each other transversely of the blade to permit rotating of a locking member.

References Cited UNITED STATES PATENTS 2,049,466 8/1936 Minich 5 l9 2,119,813 6/1938 Keefer 5l9 2,819,562 1/1958 Barnes 5l9 3,352,064 11/1967 De Groot et al 5l9 FOREIGN PATENTS 834,340 3/ 1952 Germany. 604,484 7/1948 Great Britain.

LESTER M. SWINGLE, Primary Examiner 

